This invention relates generally to xerographic copying apparatus and, more particularly, to a contact fusing system for fixing electroscopic toner material to a support member.
In the process of xerography, a light image of an original to be copied is typically recorded in the form of a latent electrostatic image upon a photosensitive member with subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual image can be either fixed directly upon the photosensitive member or transferred from the member to a sheet of plain paper with subsequent affixing of the image thereto.
In order to permanently affix or fuse electroscopic toner material onto a support member by heat, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This action causes the toner to be absorbed to some extent into the fibers of the support member which, in many instances, constitutes plain paper. Thereafter, as the toner material cools, solidification of the toner material occurs causing the toner material to be firmly bonded to the support member. In both the xerographic as well as the electrographic recording arts, the use of thermal energy for fixing toner images onto a support member is old and well known.
One approach to thermal fusing of electroscopic toner images onto a support has been to pass the support with the toner images thereon between a pair of opposed roller members, at least one of which is internally heated. During operation of a fusing system of this type, the support member to which the toner images are electrostatically adhered is moved through the nip formed between the rolls with the toner image contacting the fuser roll to thereby effect heating of the toner images within the nip.
As the copy sheet passes out of the nip formed by the fuser roll and the backup roll, it is necessary to provide means such as stripper members or fingers to insure that the copy paper proceeds along a predetermined path from the aforementioned nip to a conveyor belt or the like for moving the copy paper towards the exit of the machine or apparatus.
Accordingly, it is the primary object of this invention to provide a new and improved apparatus for stripping copy sheets from a heated fuser member.
Another object of this invention is to provide a new and improved heat and pressure fuser for fixing toner images to support or copy sheets.
Still another object of this invention is to provide an integral stripper finger and combination support and bias means therefor wherein the support and bias means comprises a unitary construction.
Yet another object of this invention is to provide a new and improved stripper means for removing copy sheets from a heated fuser member wherein the stripper finger and a combination support bias means therefor are repositionable to vary the contact pressure between the stripper finger and the heated fuser roll member.